Here's why:

* Convergent Plate Boundaries: These boundaries occur when two tectonic plates collide. The immense pressure and force of the collision causes the rocks to buckle, bend, and fold, creating the characteristic folds that form mountains.

* Types of Convergent Boundaries:

* Continental-Continental Convergence: When two continental plates collide, their similar densities cause them to buckle and fold, forming mountain ranges like the Himalayas.

* Oceanic-Continental Convergence: When an oceanic plate collides with a continental plate, the denser oceanic plate subducts (dives) beneath the continental plate. This process can also create folded mountains on the continental plate.

Important Note: While convergent boundaries are the primary cause of folded mountains, other geological processes can also contribute, including:

* Faulting: The intense pressure can also cause rocks to fracture and move along fault lines, further shaping the mountains.

* Erosion: Erosion by wind, water, and ice can sculpt and expose the folded rock layers, revealing the mountain's structure.